Multimedia player displaying 2 projection images

ABSTRACT

A multimedia player for providing two projection images is provided. The multimedia player for displaying two projection images includes: a first projection unit displaying a first projection image; and a second projection unit displaying a second projection image. The first projection unit includes: a first driving unit controlling an operation of the first projection unit and providing an image signal on the first projection image to be displayed; a first light source unit; a first light modulation device outputting the first projection image by modulating light provided from the light source in response to the image signal of the first projection image; and a first projection lens unit magnifying and projecting an image that is output from the first light modulation device. The structure of the first projection unit is the same as that of the second projection unit. The multimedia player further includes a screen sensing unit sensing a color of an area in which an image is to be displayed. The first and second driving units detect a complementary color of a color sensed by the screen sensing unit and increase brightness of a light source corresponding to the complementary color among light sources of the first and second light source units or image data corresponding to the complementary color among image data to be displayed, thereby improving visibility.

This is a National Phase Application filed under 35 U.S.C. 371 as anational stage of PCT/KR2008/000968, with the filing date of Feb. 19,2008, an application claiming priority benefit from Korean PatentApplication No. 10-2007-0017108, filed Feb. 20, 2007 and10-2008-0014706, filed Feb. 19, 2008, the entire content of each ofwhich is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a multimedia player for providing twoprojection images, and more particularly, to a multimedia player forproviding two projection images capable of displaying a clear image inany time without additional setting procedures.

BACKGROUND ART

As performance and a function of a mobile communication terminal havebeen improved, various types of multimedia contents have been provided.As the function of the mobile communication terminal is developed,digital display devices such as LCDs are used so as to provide a displaywith high image quality. However, the display devices have a limit in asize of an image. In order to solve the disadvantage, a size of adisplay screen of the mobile communication terminal has to be increased.Accordingly, a problem in that the size of the mobile communicationterminal is increased is caused. This problem interrupts miniaturizationand light-weighting of the mobile communication terminal and increasespower consumption.

In order to solve this problem, methods in which a projection functionis added to a mobile communication terminal have been suggested. Thesuggested methods include Korean Patent Application No. 10-2000-56807entitled as “Wireless Terminal Device Having Projection Function andMethod of Displaying the Same” and Korean Utility Model RegistrationApplication No. 20-263336 entitled as “Mobile Video Phone Coupled withLiquid Crystal Projector”. Since in the aforementioned methods, only aprojection function is added to the mobile communication terminal, it isinconvenient to control a size of a scanning screen and resolution. Onthe other hand, in Korean Patent Application No. 10-2003-97087 entitledas “Mobile Communication Terminal for Scanning Projector Image inVarious Directions”, a mobile communication terminal in which it ispossible to scan a projector image in various directions by installing aprojector module protrudedly from the mobile communication terminal androtating the projector module has been suggested.

In the aforementioned methods, since a distance between a mobilecommunication terminal and a screen is not fixed and changed accordingto situations, it is necessary to change settings of an optical systemso as to focus an image according to the distance between the mobilecommunication terminal and the screen whenever the image is projectedand displayed. Specifically, it is very difficult to accurately adjustthe focus of the image on the screen by using the projection modules ofthe mobile communication terminal every time.

Accordingly, in the present invention, a multimedia player capable ofproviding two clear projection image at any time without additionalsettings of an optical system whenever a user uses the multimedia playeris suggested.

DISCLOSURE Technical Problem

The present invention provides a multimedia player capable of displayingtwo clear projection images at any time without additionally setting anoptical system whenever the multimedia player is used.

The present invention also provides a multimedia player for providingtwo projection screens capable of concurrently displaying the twoprojection images to be used as a screen for an input device and ascreen for outputting an image.

The present invention also provides a small multimedia player with lowpower consumption capable of clearly displaying two different projectionimages at any time.

Technical Solution

According to an aspect of the present invention, there is provided anmultimedia player capable of displaying two projection images, themultimedia player comprising: a first projection unit displaying a firstprojection image; and a second projection unit displaying a secondprojection image, wherein the first projection unit comprises: a firstdriving unit controlling an operation of the first projection unit andproviding an image signal of the first projection image to be displayed;a first light source unit; a first light modulation device outputtingthe first projection image by modulating light provided from the lightsource in response to the image signal on the first projection image;and a first projection lens unit magnifying and projecting an image thatis output from the first light modulation device, and wherein the secondprojection unit comprises: a second driving unit controlling anoperation of the second projection unit and providing an image signal onthe second projection image to be displayed; a second light source unit;a second light modulation device outputting the second projection imageby modulating light provided from the light source unit in response tothe image signal of the second projection image; and a second projectionlens unit magnifying and projecting an image that is output from thesecond light modulation device.

In the above aspect of the present invention, focal lengths of the firstand second projection lens units may be initially set so that an imageis projected at a predetermined position extended from a bottom planeover which the multimedia player is located. Ones of a LCD (liquidcrystal display) panel, a DMD (digital micrometer device), a GLV(grating light valve) device, and an LCoS (liquid crystal on silicon)device may be selectively used as the first and second light modulationdevices.

In addition, the aforementioned multimedia player may further include ascreen sensing unit sensing a color of an area in which an image is tobe displayed. The first and second driving units may detect acomplementary color of a sensed color of a bottom plane by using thescreen sensing unit and increase brightness of a light sourcecorresponding to the complementary color among light sources of thefirst and second light source units. Alternatively, the first and seconddriving units may detect a complementary color of a sensed color of abottom plane by using the screen sensing unit and increase image datacorresponding to the complementary color among image data to bedisplayed.

According to another aspect of the present invention, there is provideda multimedia player providing two projection images which operates in adual mode by concurrently providing first and second images by using asingle light source unit, the multimedia player comprising: a drivingunit controlling an entire operation and providing first and secondimage signals; a light source; a polarization beam splitter splittinglight provided from the light source unit into first and secondpolarized light beams; a first light modulation device located in a paththrough which the first polarized light beam provided from the PBS(polarization beam splitter) proceeds, the first light modulation devicemodulating the first polarized light beam in response to a first imagesignal and providing the first image; a first projection lens unitmagnifying and projecting the first image provided from the first lightmodulation device; a second light modulation device located in a paththrough which the second polarized light beam provided from the PBSproceeds, the second light modulation device modulating the secondpolarized light beam in response to a second image signal and providingthe second image; and a second projection lens unit magnifying andprojecting the second image provided from the second light modulationdevice, wherein images projected from the first and second projectionlens units are formed at previously set first and second positions.

In the above aspect of the present invention, focal lengths of the firstand second projection lens units may be initially set so that first andsecond images are projected at first and second predetermined positionsextended from a bottom plane over which the multimedia player islocated. A lamp unit of the light source unit may be constructed withLED arrays constructed with red (R), blue (B), and green (G) LEDs. Thefirst and second light modulation devices may be transmissive orreflective light modulation devices.

Advantageous Effects

In the present invention, it is possible to display an image having asize greater than a predetermined size regardless of an entire size of amultimedia player for providing two projection screens.

In addition, the multimedia player according to an embodiment of thepresent invention forms an image at a predetermined distance from themultimedia player at any time by using a position extended from a bottomplane that is vertically or horizontally located as a screen.Accordingly, it is possible to see a clear projection image at any timeby initially setting a focus of an optical system for performing aprojection function. It is unnecessary to set the optical systemwhenever the multimedia player is used.

In addition, the multimedia player according to an embodiment of thepresent invention can project two different images onto a bottom planeby using a light source. The aforementioned multimedia player accordingto an embodiment of the present invention can be applied to a mobile orportable terminal which requires a small size and low power consumption.

In addition, the multimedia player according to an embodiment of thepresent invention senses a color of the bottom plane that is a screenand highlights the complementary color of the color of the bottom plane.It is possible to improve visibility of the image.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram illustrating components for performing aprojection function of a multimedia player for providing two projectionimages according to a first embodiment of the present invention.

FIG. 2 illustrates an example of a state in the multimedia player forproviding two projection images according to the first embodiment of thepresent invention operates.

FIG. 3 is a schematic diagram illustrating an inner structure of amultimedia player for providing two projection images according to asecond embodiment of the present invention.

BEST MODE First Embodiment

Hereinafter, a structure and an operation of a multimedia player forproviding two projection images according to a first embodiment of thepresent invention will be described in detail with reference to theaccompanying drawings.

In the specification, the multimedia player includes all the terminalscapable of reproducing multimedia contents, still images, or movingpictures, such as a mobile communication terminal, a personal digitalassistant (PDA), a portable multimedia player (PMP), a play stationportable (PSP), and the like.

FIG. 1 is a schematic block diagram illustrating components forperforming a projection function of a multimedia player 10 for providingtwo projection images according to a first embodiment of the presentinvention. FIG. 2 illustrates a state in which a predetermined image isdisplayed through an operation of the multimedia player 10.

Referring to FIGS. 1 and 2, the multimedia player 10 according to thefirst embodiment of the present invention includes first and secondprojection units 12 and 14. The first projection unit 12 includes afirst driving unit 102, a first light source unit 112, a first lightmodulation device 122, and a first projection lens unit 132. The secondprojection unit 14 includes a second driving unit 104, a second lightsource unit 114, a second light modulation device 124, and a secondprojection lens unit 134. However, since components of the multimediaplayer which are necessary for reproducing multimedia contents are knownto those skilled in the art, description on the components will beomitted in the specification. Only components related to the subjectmatter of the invention will be described. Hereinafter, since astructure and an operation of the first projection unit are similar tothose of the second projection unit, only the first projection unit willbe described.

The first driving unit 102 controls an operation of the first projectionunit 12 so as to display a first projection image. The first drivingunit 102 controls operations of the first light source unit 112 and thefirst light modulation device 122. Specifically, the first driving unitprovides an image signal corresponding to the first projection image tothe light modulation device so as to display a predetermined firstprojection image.

The first light source unit 112 is constructed with a lamp unit, anoptical system for uniformizing light such as a fly's eye lens, and thelike. The lamp unit may be constructed with LEDs. The lamp unit isconstructed with three plates respectively constructed with blue, green,red LED arrays in which red (R), green (G), and blue (B) LED modules areseparated from one another. The LED arrays are sequentially drivenaccording to a frequency of 180 Hz so as to sequentially provide lightbeams with R, G, and B colors. On the other hand, a lamp unit of a lightsource unit 300 according to another embodiment of the present inventionis constructed with two plates in which red LEDs and blue LEDs aresequentially arranged in a module to construct an LED array, and greenLEDs are sequentially arranged to construct an LED array or one plate inwhich red, green and blue LEDs are sequentially arranged to construct anLED array. In addition, the lamp unit of the first light source unit 112according to the embodiment may be constructed with organic lightemitting diodes (OLEDs), laser diodes (LDs), and the like, in additionto the LED array or constructed with a point light source or a surfacelight source.

Since the first light source unit is known to those skilled in the art,detailed description on the first light source unit will be omittedthroughout the specification.

The first light modulation device 122 outputs a predetermined image bymodulating light provided from the first light source unit in responseto an image signal provided from the first driving unit. A transmissiveor reflective light modulation device such as a liquid crystal display(LCD) panel, a digital micromirror device (DMD), a grating light valve(GLV) device, a liquid crystal on silicon (LCoS), and the like may beselectively used as the first light modulation device 122.

The first projection lens unit 132 magnifies and projects an image thatis output from the first light modulation device 122.

As shown in FIG. 2, an image projected from the projection lens unit ofthe multimedia player according to the first embodiment of the presentinvention is formed at a predetermined position (‘a’ area of FIG. 2)extended from a bottom plane over which a housing unit is located.Accordingly, the multimedia player according to the first embodiment ofthe present invention forms an image at a position spaced apart from theprojection lens unit by a constant distance (‘d’ of FIG. 2) by using thebottom plane as a screen. As a result, if an optical system of themultimedia player comes into focus by initially setting the opticalsystem once, it is unnecessary to additionally set the optical systemwhenever the optical system is used. It is possible to display a clearimage at any time.

As shown in FIG. 2, an image corresponding to an input device such as akeyboard is displayed on one of the two projection screens. The imageserves as a function of the input device such as a virtual keyboard anda virtual mouse. At this time, in order to provide functions of thevirtual keyboard and the virtual mouse, the multimedia player furtherincludes a complementary metal-oxide semiconductor (CMOS) camera and aninfrared laser. A position pointed by a finger is recognized in realtime by capturing and analyzing the image of the virtual keyboard inreal time by using the CMOS camera. It is possible to determine whetherthe bottom plane is touched by sensing reflection of a laser beam due toa finger that contacts the bottom plane by using the infrared laser.Although an example of a method of providing a virtual keyboard functionby using the CMOS camera and the infrared laser is described, varioustechniques may be also applied.

Second Embodiment

Hereinafter, a structure and an operation of a multimedia player forproviding two projection images according to a second embodiment of thepresent invention will be described in detail with reference to FIG. 3.FIG. 3 is a schematic diagram illustrating an inner structure of amultimedia player for providing two projection images according to asecond embodiment of the present invention. The multimedia playeraccording to the second embodiment provides two projection images byusing a light source unit and a polarization beam splitter (PBS).

Referring to FIG. 3, the multimedia player 30 according to the secondembodiment includes a single light source unit 300, a PBS 310, a firstlight modulation device 320, a first projection lens unit 330, a secondlight modulation device 340, a second projection lens unit 350, and adriving unit (not shown).

The driving unit controls an entire operation of the multimedia player30. The driving unit controls operations of the light source unit 300,and the first and second light modulation devices 320 and 340.Specifically, in order to display two different images, the driving unitprovides first and second image signals corresponding to first andsecond images to the first and second light modulation devices 320 and340, respectively.

Since the light source unit 300 is the same as the light source unitaccording to the first embodiment, repeated description on the lightsource unit 300 will be omitted.

The PBS 310 provides first and second polarized light beams alongdifferent light paths by splitting light provided from the light sourceunit into two orthogonal light beams which are first and secondpolarized light beams (for example, P-wave and S-wave).

It is known that light is a wave. A wave is constructed with twoorthogonal wave components which are a P-wave and an S-wave. The P-waveis a longitudinal wave of which a propagation direction is the same asan oscillation direction of a medium. The S-wave is a transverse wave ofwhich a propagation direction is perpendicular to an oscillationdirection of a medium. Since terms of the P-wave and the S-wave areknown to those skilled in the art, detailed description on the termswill be omitted.

A path of the P-wave of light provided from the light source unit ischanged by passing through the PBS 310, thereby proceeding along adirection perpendicular to the propagation direction. A path of theS-wave of light provided by the light source unit is maintained bypassing through the PBS 310, thereby proceeding along a direction thatis the same as the propagation direction.

The first light modulation device 320 is located in a path through whichthe P-wave that is the first polarized wave provided from the PBS 310proceeds so as to provide a first image by modulating the firstpolarized wave in response to a first image signal provided by thedriving unit. The first light modulation device 320 may use atransmissive light modulation device. The transmissive light modulationdevice may be a transmissive micro display device.

The first projection lens unit 330 is located in front of the firstlight modulation device to magnify and project the first image providedfrom the first light modulation device.

The second light modulation device 340 is located in the path throughwhich the S-wave that is the second polarized wave provided from the PBS310 proceeds so as to provide a second image by modulating the secondpolarized wave according to a second image signal provided by thedriving unit. The second light modulation device 340 may use areflective light modulation device. An LCoS, reflective LCD, or DMDdevice may be selectively used as the reflective light modulationdevice.

In a case where the second light modulation device is a reflective LCoSlight modulation device, the second projection lens unit 350 is locatedin a path through which light reflected from the second light modulationdevice and reflected from the PBS is output so as to magnify and projectthe second image provided from the second light modulation device. Onthe other hand, in a case where the second light modulation device is areflective DMD light modulation device, it is possible to provide apredetermined image at a desired position by adjusting an angle of alocation of the second light modulation device and positioning a secondprojection lens unit in a path of light.

As shown in FIG. 3, different images are formed on screens (‘a’ and ‘b’)which are located at different positions by constructing the first lightmodulation device with the transmissive light modulation device andconstructing the second light modulation device with a reflective lightmodulation device.

In another embodiment of the present invention, both of the first andsecond light modulation devices may be constructed with transmissivelight modulation devices or reflective light modulation devices. Inaddition, it is possible to change angles in which the first and secondprojection images are formed by freely changing a path of light that isoutput from the first and second light modulation devices by using areflection mirror.

The multimedia player for providing two projection images according tothe second embodiment operates in a dual mode by concurrently providingdifferent first and second images at different positions by using asingle light source unit. Specifically, images projected from the firstand second projection lens units of the multimedia player according tothe second embodiment are formed at predetermined positions (‘a’ and ‘b’areas of FIG. 3) extended from a bottom plane.

Accordingly, the multimedia player according to the second embodiment ofthe present invention forms an image at a position spaced apart from thefirst and second projection lens units by a constant distance by using abottom plane as a screen. As a result, if an optical system of themultimedia player comes into focus by initially setting the opticalsystem once, it is unnecessary to additionally set the optical systemwhenever the multimedia player is used. It is possible to display aclear image at any time.

Since the multimedia player for providing two projection imagesaccording to the second embodiment can concurrently project twodifferent images by using a light source unit, it is possible tominiaturize the multimedia player and reduce the entire powerconsumption. Accordingly, the multimedia player according to the secondembodiment may be applied to a mobile or portable terminal. In addition,it is possible to display a clear image at any time by initially settingan optical system once in a case where the multimedia player forproviding two projection images according to the second embodiment usesa bottom plane over which the housing unit is located as a screen.

Third Embodiment

Hereinafter, a structure and an operation of a multimedia player forproviding two projection images according to a third embodiment of thepresent invention will be described in detail. The multiplayer playeraccording to the third embodiment provides two clear projection imagesby sensing a color of a bottom plane that serves as a screen andincreasing brightness of a complementary color of the sensed color anddisplaying the complementary color of the sensed color. Description oncomponents of the multimedia player according to the third embodimentwhich are the same as those of the multimedia player according to thefirst embodiment will be omitted.

The multimedia player according to the third embodiment further includesa screen sensing unit in addition to the components of the multimediaplayer according to the first embodiment. The screen sensing unit may beconstructed with a color sensor for sensing colors or a CMOS camera. Thedriving unit of the multimedia player senses the color of the bottomplane to be a screen by using a screen sensing unit or captures an imageof the bottom plane by using the CMOS camera. Next, a mean color isobtained by calculating a mean value of the color of the bottom planefrom the captured image or sensed color. Then, the complementary colorof the mean color is determined. For example, in a case where a meancolor of the bottom plane is bluish green, red that is the complementarycolor of bluish green is determined. An image is modified so thatbrightness of a light source corresponding to a complementary coloramong R, G, and B light sources is increased by using the determinedcomplementary color and so that brightness of a light sourcecorresponding to the bottom color is decreased. Visibility of the imageformed on the screen is improved by increasing a contrast ratio of theimage through this procedure of modifying brightness of light sources.For example, in a case where the color of the bottom plane is bluishgreen, brightness of an R-light source is increased within apredetermined range, and brightness of G and B light sources aredecreased within predetermined ranges.

On the other hand, the first and second driving unit according to anembodiment of the present invention may modify image data to bedisplayed instead of controlling brightness of light sources. Morespecifically, the first and second driving units generates new imagedata by increasing image data corresponding to the complementary coloramong image data and decreasing image data corresponding to the color ofthe bottom plane and display the new image data. In the embodiment, itis possible to improve visibility of images to be displayed on thebottom plane.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those skilled in the art that various changes in form and details maybe made therein without departing from the spirit and scope of thepresent invention as defined by the appended claims. For example, in anembodiment of the present invention, the structure of the lamp unit ofthe light source, the light modulation device, and the like may bechanged and used in various manners so as to improve the entireperformance of the multimedia player. All differences within the scopewill be construed as being included in the present invention as definedby the appended claims.

INDUSTRIAL APPLICABILITY

A technique according to an embodiment of the present invention may bewidely used for a mobile communication terminal or mobile personalinformation terminal such as a portable multimedia player (PMP) orpersonal digital assistant (PDA).

1. A multimedia player capable of displaying two projection images, themultimedia player comprising: a first projection unit displaying a firstprojection image; and a second projection unit displaying a secondprojection image, wherein the first projection unit comprises: a firstdriving unit controlling an operation of the first projection unit andproviding an image signal of the first projection image to be displayed;a first light source unit; a first light modulation device outputtingthe first projection image by modulating light provided from the lightsource in response to the image signal of the first projection image;and a first projection lens unit magnifying and projecting an image thatis output from the first light modulation device, and wherein the secondprojection unit comprises: a second driving unit by controlling anoperation of the second projection unit and providing an image signal ofthe second projection image to be displayed; a second light source unit;a second light modulation device outputting the second projection imageby modulating light provided from the light source unit in response tothe image signal of the second projection image; and a second projectionlens unit magnifying and projecting an image that is output from thesecond light modulation device, wherein focal lengths of the first andsecond projection lens units are initially set so that an image isprojected at a predetermined position extended from a bottom plane overwhich the multimedia player is located, wherein the first light sourceunit and the second light source unit are constructed with LED arraysconstructed with red (R), blue (B), and green (G) LEDs, and the LEDarrays are sequentially driven according to a predetermined frequency tosequentially provide light beams with R, G and B colors, the multimediaplayer further comprising a screen sensing unit sensing a color of anarea in which an image is to be displayed, wherein the first and seconddriving units detect a complementary color of the sensed color of thebottom plane by using the screen sensing unit and increase brightness ofalight source corresponding to the complementary color among lightsources of the first and second light source units.
 2. The multimediaplayer of claim 1, wherein ones of a LCD (liquid crystal display) panel,a DMD (digital micrometer device), a GLV (grating light valve) device,and a LCoS (liquid crystal on silicon) device are selectively used asthe first and second light modulation devices.
 3. The multimedia playerof claim 1, further comprising a screen sensing unit sensing a color ofan area in which an image is to be displayed, wherein the first andsecond driving units detect a complementary color of the sensed color ofthe bottom plane by using the screen sensing unit and increase imagedata corresponding to the complementary color among image data to bedisplayed.
 4. A multimedia player providing two projection images whichoperates in a dual mode by concurrently providing first and secondimages by using a single light source unit, the multimedia playercomprising: a driving unit controlling an entire operation and providingfirst and second image signals; a light source; a polarization beamsplitter splitting light provided from the light source unit into firstand second polarized light beams; a first light modulation devicelocated in a path through which the first polarized light beam providedfrom the PBS (polarization beam splitter) proceeds, the first lightmodulation device modulating the first polarized light beam in responseto a first image signal and providing the first image; a firstprojection lens unit magnifying and projecting the first image providedfrom the first light modulation device; a second light modulation devicelocated in a path through which the second polarized light beam providedfrom the PBS proceeds, the second light modulation device modulating thesecond polarized light beam in response to a second image signal andproviding the second image; and a second projection lens unit magnifyingand projecting the second image provided from the second lightmodulation device, wherein images projected from the first and secondprojection lens units are formed at previously set first and secondpositions, wherein focal lengths of the first and second projection lensunits are initially set so that an image is projected at a predeterminedposition extended from a bottom plane over which the multimedia playeris located, and wherein the light source is constructed with LED arraysconstructed with red (R), blue (B), and green (G) LEDs, and the LEDarrays are sequentially driven according to a predetermined frequency tosequentially provide light beams with R, G and B colors, the multimediaplayer comprising a screen sensing unit sensing a color of an area inwhich an image is to be displayed, wherein the driving unit detects acomplementary color of the sensed color of the bottom plane by using thescreen sensing unit and increases brightness of a light sourcecorresponding to the complementary color among light sources of thelight source unit.
 5. The multimedia player of claim 4, wherein thefirst light modulation device is a transmissive light modulation deviceor reflective light modulation device.
 6. The multimedia player of claim4, wherein the second light modulation device is a transmissive lightmodulation device or reflective light modulation device.
 7. Themultimedia player of claim 4, further comprising a screen sensing unitsensing a color of an area in which an image is to be displayed, whereinthe driving unit detects a complementary color of the sensed color ofthe bottom plane by using the screen sensing unit and increases imagedata corresponding to the complementary color among image data to bedisplayed.